Hook latch operating mechanism



@at 7, B952 c. MoJ. RQBERSQN Zlpm HOOK LATCH OPERTING MECHNISM Filed oct. 17, 195o 3 Sheets-Sheet l 'a INVENTOR,

BY w/M,

@et 7, i952 Filed Oct. 17, 1950 C. MCJ. ROB

ERsoN 296%,101

HOOK LATCH OPERATING MECHANISM 3 Sheets-Sheet 2 IN VEN TOR. @LA ODE M'- ROBERS ON MMM/Mw ATTORNEYS @ein 7, 1952 c. MoJ. ROBERSON 2951391@ HOOK LATCH OPERATING MECHANISM AFiled. Oct. 17, 1950 3 Sheets-Sheet 3 JNVENTOR. @LBUDE M- ROBERSON )ATTORNEYS .tached from the drill stem.v

Vdrilling operation and yet allow rotation of the Patented Oct. 7, 1952 2,613,101 HOOK LATCH OPERATING MECHANISM Claude M'cJunis-Itoberson, Shreveport, La. Application October 1'l7`,11950, Serial No. 190,516

Y.This invention relates to apparatus for the V.

4control of latches on hooks and particularly to latches used on oil Well hooks. Y

Hooks of the type herein referred to are particularly adapted for the control of oil well ap- 5 paratus used in supporting the drill stem and in 9,., lifting and. positioning sections of pipe to be at.-

tached to the drill stem in the well, or in supporting and controlling sections of pipe to be de- Hooks of this general type are described VVand s .claimed in my co-pending application, Serial No.

188,031, ledOctober 2, 1950, and in my'Patent No. 2,519,288. Reference is made torthese ,disclosures for a description of the apparatus with Whichsuch hooks are used and for a more complete description of the hook itself; The present l invention is particularly directed to means for controlling the operation of the hook latch.

In the method most commonly used fordrillingr. oilwells, rotary drilling, a derrick is posi-M '.tioned over the Well siteto make convenient han- -dling of the pipe used in the drilling operation possible; A crown block with sheaves over which came,` Called the drilling une, is pessedissuspended from the top of the derrick. The drilling lineis passed around a plurality of sheavesof am lower, or. travelling block. Manipulation of the drilling line causes vertical movementof the .sus pended travelling block within the derrick. From the.. travelling block a hook is suspended which, is used to support the rotary swivel during the drilling operation and to hold the pipe stands to be added to or disconnected from thedrill stem in the well. The swivel has a bail attached thereto which is suspended from the hook. 1.., The rotary swivel is a large and expensive piecem" i of equipment which must be capable of sustaining the weight o1-` the entire drill stem during the V-hook during the process of adding or removing pipe stands to or from the drillstem. Therefore, it is desirable that thellatch be readily opened and 50 closed?, y A The latch position could be controlled bythe workers on the derrick floor, but it is more conv venient and lessdangerous if the operation is i performed lata remote position by the driller. 55,

20 Claims. (Cl. 294-82) 40.', present invention comprises generally a pivoted With these considerations in mind, a latch-operating mechanism for the hook has been devised that may be easily and conveniently operated by iluid pressure, controlled, for instance, from the drillers position.

During the drilling operation, it is frequently necessary toattach sections of pipe to the drill connectedmust be rotated relative to one another, f since the joints between pipe sections are threadedly engaged. The hook, then, should be freely rotatable, but the hook body should remain stationary, so that the drilling line will not be twisted or the travelling block damaged.

It is necessary that fluid under pressure be supplied to the latch operating mechanism from some external source in order to actuate that mechanism. If long fluid pressure lines were led from such a source of iiuid under pressure directly to the latch-operating mechanism adjacent the hook, these lines would be in danger of becoming twisted and entangled when the hook was rotated. To avert this danger, it is proposed that duid under pressure for the operation /of the hook latch be supplied to a passage extending through the body of the hook, from thetoplthereof, and led throughthe passage to a point adjacent the latch-operating mechanism. In suchcase, it is not necessary that there be any long fluid line adjacent the hook, so that Y The hook latch operating mechanism of the latch member vfor closing the bail-receiving notch ofthe hook and a fluid-operated mechanism to ,control the opening and closing of the latch y member.

In one form of the invention, this iiu`id-operated` mechanism includes a piston .mounted in a iluid chamber and having a piston rod extending outwardly therefrom, and connected at its outer end to a locking` lever which engages one arm of a bell crank lever. The other 4arm ofthe bell crank lever engages an extension arm of the pivoted latch member to cause pivotal movement of the latch member when the bell crank lever is moved. i

v1n the speciiic construction of this form of the invention which is herein described, the bell crank lever is spring biased to a position such that the latch is closed. The positions of the latch member and its associated apparatus when the latch is closed will be hereinafter referred to as the normal positions thereof. When the latch is to be opened, fluid under pressure is supplied to the piston chamber, the piston and its Aassociated rod and locking lever being moved to pivot the bell crank lever against the action of the spring and open the latch member. When the latch member is again to be closed, the pressure of the fluid is released and the piston allowed to return to its normal position. At the same time, the swivel bail, urged downwardly by the weight of the swivel, will move the latch members extension arm downwardly, thus causing the latch member to return to its closed position. The spring means concurrently returns the bell crank lever and the locking lever to their previous positions, the locking lever then locking the extension arm of the latch member in position.

In another form of the invention, the locking lever and the latch-moving mechanism are controlled by separate pistons. The direction of fluid travel is such that the locking lever is moved to its inoperative position before actu ation of the latch-moving mechanism. Both the locking lever and the latch-moving mechanism are spring-urged to their normal positions.

The invention will be reference to the accompanying drawings in which a preferred embodiment of the invention is shown. However, it is to be understood that such further disclosure and description is by way of exemplification and the invention is not limited thereto, except to the extent set forth in the subjoined claims.

In the drawings:

Fig. l is an elevation view, partly in section, of a hook constructed in accordance with the invention,

Fig. 2 is a view of the hook, similar to Fig. 1, showing the latch member in open position,

Fig. 3 is a detail elevation view of the lower part of the hook showing a modified embodiment of the invention, with parts of the hook being shown in section,

paratus of Fig. 1, and

Fig. is an elevation view, partly in section, of a further modified form of the hook.

The hook assembly` illustrated in the drawings is of the type used in oil well drilling, and comprises, Fig. 1, a hook I and a hook body 2. The hook body has a pair of ears 3 extending from its upper end for connection to a bail 3 supported by the usual travelling block (not shown).

The hook body 2 has a cylindrical chamber 4 extending longitudinally thereof. The inner wall of the hook body extends inwardly at its lower end to form a shoulder 5 upon which is supported a bearing member 6. Ball bearings 'I are interposed between upper and lower bearing rings 1a and 1b between the lower surface of the bearing member 6 and the shoulder 5, to allow rotation of the bearing member relative to the wall of the hook body.

A cylindrical piston 8 is positioned within the chamber 4 and has a pair of sealing rings 9 in slots in its peripheral edge to prevent the escape of fluid from one of its sides to the other. A piston rod I0 extends through an upwardly converging bore in the piston 8 and is threadedly further described with 4 engaged with a nut II which rests on the upper side of the piston and securely connects the piston to the piston rod.

The piston rod extends downwardly through the bearing member 6 and has its lower end secured to the shank of the hook I. Appropriate sealing packing I2 is positioned between the piston rod I0 vand the bearing member 6 and between the outer perpheryof the lower portion of the bearing member and the wall of the hook body to prevent uid from escaping from the chamber. A plate I3 is bolted to the lower end of the bearing member to keep the packing in position.

Fluid under pressure is admitted to the cylinder 4 through a fluid supply pipe I4 threadedly engaged in a passage I5 through the wall of the hook body adjacent the bearing member 6. When uid is admitted to the cylinder, it will exert a force on the piston 8, tending to force it and the hook which is connected to the lower end of the piston rod, upwardly.

The peripheral surface of the bearing member 8 is spaced slightly from the wall of the hook body 2, s0 that fluid within the cylinder 4 may communicate with both sides of the bearing member. As a result, the pressure exerted on the bearing member when uid under pressure is supplied to the cylinder 4 is greatly reduced, thus decreasing the tendency for the bearing member to be so jammed against the shoulder of the hook body that it would resist rotation with the hook.

A cap I6 closes the upper end of the hook body to exclude dirt and moisture therefrom and has a plurality of vent holes I6 through it through which air compressed by upward movement of the piston may be discharged.

The hook I has a bail-receiving notch II at one side within which the bail I'I of the rotary swivel is received. A latch member I8 is pivoted on a pin I9 on the hook and fits, when in the closed position shown in Fig. 1, between a pair of outstanding ears 20 integral with the hook, to close the bail-receiving notch I'I.

The latch member I8 has an extension 2I protruding into a space 22 formed within the hook. A bell crank lever 23 is pivotally mounted at 24 vwithin said space and has an actuating arm 23a for the extension which lies beneath and slightly spaced from the extension when the latch member is in its closed position. The other arm 23h of the bell crank lever is connected to a push rod 25 reciprocally mounted within a cylindrically-shaped bore 26 formed in the hook. The outer end of the rod 25 extends through a central aperture lformed byan annular shoulder 21 near the outer end of the bore. A compression spring 28 is interposed between the shoulder 21 and a stop washer 29 tted about the push rod 25 and held in a predetermined position by a pin 30 which passes through the rod 25. 'I'he biasing action of the spring exerted through the rod 25 normally urges the bell crank lever 23 to the position shown 'in Fig. l with its arm 23a adjacent the lower portion of the surface bounding the space within the hook.

Another cylindrically-shaped bore 3I also extends from the space in the hook and has a sealing plug 32 at its outer end. A piston 33 is positioned for reciprocation within the bore 3l andcarries a piston rod 34 at its inner side. The plug 32 and the piston 33 form the two ends of an expansible fluid chamber 35 within the cy- Vclosed position between the ears 20.

amener lin'drical bore 3|; Fluid is admitted under pressure to the expansible' fluid chamber through a section of iiexible tubing A which has one of its ends communicating with .a passage 3l' extending through the sealing plug 32. The piston rod 34 is connected to one end of a locking lever 38 at its end remote from the piston. The locking lever is pivoted on a pin 39 mounted in said space in the hook. The opposite end 38a of the locking lever bears normally against the upper side of the extension 2| toV prevent the latch member from swinging counter-clockwise about its pivot I3, and thereby locks the latch member in its closed position.

When fluid-under pressure is supplied to the chamber 35 through the flexible tubing 35, the piston 33 is forced away from the sealing plug 32. The piston carries the piston rod 34 with it to cause pivotal movement of the locking lever 38 about its pivot pin 39 in a counter-clockwise direction, moving the end 38a of the locking lever away from the upper end of the extension 2 l, thus freeing the extension for movement. This movement of the locking lever 38 causes a clockwise movement of the bell crank lever 23, and the arm' 23b thereof forces the push rod 25 outwardly within the cylindrical bore 26 against the action of the spring 28. Simultaneously, the arm 23a of the bell crank lever moves into engagement with the lower side of the extension 2l and swings the latch I8 in a counter-clockwise direction to its open position,shown in Fig. 2.

When the latch member is to be moved to its closed position, the supply of iiuid to the expansible chamber 35 is turned off. The bail il", urged downwardly by the weight of the swivel, will move the extension 2| downwardly, thus causing clockwise movement of the latch member I3 to its The bell crank lever 23 will also be moved by the extension in a counter-clockwise direction.

At vthe same time, the push rod 25 will be carried inwardly by the bell crank lever arm 23h towards its normal position. After the latch member comes to rest in its normal position, the force of the spring 2 8 continues to operate to move the push rod 25 farther inwardly, thus moving the bell crank lever farther in the counter-clockwise direction till the arm 23a thereof bears against the surface deiining the space 22 in the hook. The loekinglever 38 will also be moved by movement of the push rod 25 and the bell crank lever arm `23h in a clockwise direction till its end 38a is positioned above the extension 22. The extension at this time will be locked in position by the locking lever because it is restrained thereby against pivotal movement ina counter-clockwise direction. Thelatch member, consqeuently, cannot open accidentally.

The clockwise movement of the locking lever 33 also moves the piston rod and piston outwardly, preparing the latch mechanism for itsnext operation.

`The upper end of the iiexible tubing 36 extends through a passage 43 in a bearing collar 4| pinned to the piston rod I3 of the main fluid cylinder. This end of the tubing communicates with a iiuid passage 42 extending upwardly through the piston rod I5 to a larger axial bore 43 in the upper end of the piston rod. Fluid for actuating the piston 33 is introduced through a fluid-conducting tube 44 which extends through the cap i3 and into, and to near the bottom of the bore 43 when the piston 8 is in its uppermost position. The fluid-conducting tube 44 lpasses through a piston and piston rod about the tube.,

The upper end of the metal tube 44 which extends through the cap I6, communicates with the outlet of a fluid connection block 43, bolted to the v upper side of the cap. Fluid under pressure is supplied to the inlet of the iiuid connection block through a conduit 4'! leading to an external source (not shown), where an appropriate valve (also notshown) is positioned to regulate the supply of iiuid to the expansible chamber 35 of the latch operating mechanism. i

Thefiuid passage 42 need not be extended to the periphery of the piston rod l0, but could be drilled through the shank of the hook to the space 3| in the hook adjacent the plug 32. In such case, there would not be a passage 43 through the collar 4|, and the iiexible tubing 36 would not be necessary. Fluid for operation of the latch would be passed within the hook assembly all the way from the connection block 45 tothe expansible chamber 35.

When it is desired to operate the latch member I3 to move it to its open position so that the bail of. the rotary swivel may be inserted into or removed from `the bail-receiving notch l1, fluid under pressure is admitted through the conduit 4l' to the fluid connection block 46. It then passes through the tube 44, the bore 43 and the passage' 42 in the piston rod IU to the flexible tubing 35, and iinally to the expansible chamber 35. The latch member i3 will then be rotated in a counter-clockwise direction to its open position, as earlier described.

As explained above, the piston 8 and the piston rod l0 are forced upwardly when iiuid under pressure is supplied to the cylinder 4. However, the duid-conducting tube 44 is fixed to the cap i6 against vertical movement. As the piston moves upwardly, the piston rod slides upwardly about the tube 44, the lower end of the bore 43 in the piston rod moving toward the lower end of the tube 44. At the upper limit of travel of the piston, the lower end of the tube is still above the lower end of the bore 43. When the vfluid pressure is released, the piston moves downwardly and the piston rod slides downwardly about the tube, till at thelower limit of the piston travel, the lower end of the tube is at the upper end of the bore 43. Consequently, the tube is notdis'- placed during reciprocatory movement of the pis- When the hook is rotated to effect engagement or disengagement of a pipe joint, the piston and piston rod also rotate but the tube 44 remains stationary, the bore 43 being of large enough diameter and being properly placed so that the wall of the bore never contacts the tube.

In Fig. 3 there is shown a modified form of the latch operating mechanism of the invention. In this embodiment of the invention the mechanism for locking and actuating the latch member is positioned adjacent the bottom of the hook rather than at the side thereof, and as shown, comprisesl a latch member i3 having a pair of bearing projections 48a, 48h formed at the lower end thereof. A modified bell crank lever 23', pivoted at 24, has one of its arms 23o engageable with each of the projections 48a and 48D, but normally is biased to a position against the inner side of projection 48a by a push rod and spring combination, now to be described.

7 'The other annua of the bell crank lever 123' has 'a push 'rod 25 -connected thereto at its end 'remote from the pivot point 24". The lower end 'of the push rod projects into a cylindrical passage 26 and carries a plate 49 which is urged upwardly by a spring '28 bearing at its upper end against the `lower side of the plate and at its lower end against a plug 50 threaded into the passage 25. As outlined above, the spring 28 urges lthe push rod 25' upwardly, biasing the bell crank lever 23 to its farthest counter-clockwise position. The bell crank lever arm 23o is held against the inner side of 'the projection 48a, biasing the latch member I8' to its closed position to hold the bail |112l within the hook opening 11a.

A second cylindrical passage 3l within the space in the lower end of the hook is sealed at its lower end by a modified plug 3'2' and a piston 33 carrying a piston rod v34 is positioned within 'the passage. The piston 33 and the plug 32' form an expansible fiuid chamber 35 within the passage 3l'. Fluid under pressure is supplied to the expansible chamber through a section of flexible tubing 36'.

The outer end of the piston rod 34' is connected to one end of a modified locking lever 38', which is pivoted at 36' on the hook. The under side of the other end of the locking lever bears against the upper side of the arm 23d of the bell crank lever. The extremity 38D of this end of the locking lever normally lits into a notch I in the inner side of the projection 48h, and the upper side of this end of the locking lever normally is interposed between the projection 48D and the upper surface of the wall of the hook which surrounds the space 22 in the hook. Since the locking member is in the path of counterclockwise movement of the projection 4819 to the open position of the latch member, the l-ocking lever locks the latch member in its closed position.

The operation of this modified embodiment of the invention is similar to that of the apparatus shown in Figs. 1 and 2. However, when iiuid under pressure is' admitted to expansible chamber 35 of the apparatus shown in Fig. 3, a time delay intervenes before the latch member is opened. That time delay corresponds to the distance which the bell crank lever arm '23e must move till it contacts the inner surface of the projection 48h of the latch member.

During this interval, the locking lever 38 moves in a counter-clockwise direction out of the notch 5l and below the projection 46o, thus freeing the latch member for movement to its open position. Then the operation is the same as above, the bell crank lever arm 23e pressing the bearing projection 48h in a counter-clockwise direction to cause pivotal movement of the latch member I8 to its open position.

When the latch member I8 is to be moved to its closed position, the pressure of the fluid supplied to the expansible chamber 35' is released. The spring 26 will move the push rod 25 upwardly, moving the bell crank lever 23 in a counte-r-clockwise direction. Another time delay will ensue before the arm 23o reaches the bearing projection 48u. Then the pressure exerted by the spring will cause movement of the latch member I8 to its closed position. The locking lever 38 will again be moved in a clockwise direction by the arm 23d of the bell crank lever till its end 38h fits into the notch 5l of the projection 48h. At this time, as explained above, the locking lever 38 locks the latch member in its closed position.

In Fig. '4' there is 'shownr a 'modification ofthe means for supplying fluid to the Yfluidl operating mechanism. A fluid-conducting pipe 52 extends through and is welded, or inother suitablefman'- ner secured to the cap l6a. A section of exible tubing 53 is connected at one end of the inner end of the pipe 52 and to the inlet 54fof a rotor seal 55 at itsl other end. The rotor seal is a known device which allows fluid to be conducted from a stationary inlet, here represented as the pipe 52, to a rotatable outlet such as the outlet 56 which is bolted or otherwise secured to the end of the piston rod and rotates therewith. IThe apparatus of Fig. 3 i's otherwise identical with that shown in Fig. 1, and like parts are indicated by the same numerals with the subscript a.

A modification of the hook of Figs. 1,12 and 3 is illustrated in Fig. 5, which shows the hook lb as having a bail-receiving notch Hc, which is closed by a modified latch member |812 and re ceives a bail 11d, above described. The vlatch member 18h is pivotally mounted on a pin 19h on the hook and has a passage 51 through one of its distal extremities into which a lug 58, projecting outward of the hook, extends when the latch member is in its closed position.

The latch member |81) is recessed along its outer curved periphery to provide a surface 59, the lower end of which contacts a shoulder 60 formed on the hook when the latch member is in its open position (shown in dash lines in Fig. 5).

The portion of the latch member 18h on which the bail 11d lies is substantially channel-shaped in cross-section and ts over the portion 6I Aof the hook Ib which lies below the notch |1c. The latch member has a recessed space 62 into which one end of a link 63 projects, where it is pivotally connected to the latch member. The link 63 is connected :by a piston rod 64 to a fluid-operated piston 65 positioned in a chamber or fluid cylinder 66 formed in the hook lb. The piston rod 64 is fastened to the piston 65 by a threaded bolt 61 whose head fits in a recess in the outer surface of the piston 65. A sealing plug 68 is secured to the hook by bolts 69 and seals the outer end of the chamber 65. The sealing plug 68 and piston 5 form the ends o-f an expansible fluid chamber in the hook.

A compression spring 10 surrounding the piston rod 64 is interposed between the inner end of the chamber and the inner face of the piston 65 and normally urges the piston outwardly toward the sealing plug 68.

Fluid under pressure for operation of the piston 65 is admitted to the chamber 66 through a passage 1| in the seealing plug 68 by means to be described.

A modied locking lever 38 is pivoted midway of its length on a pin 39h mounted on the hook. One end 38o of the locking lever swings into and out of a notch 12 formed in the wall of the latch member Ib. The other end of the locking lever 38 is connected by a piston rod 13 to a fluidoperated piston 14 positioned in a hollow cylinder 15 in a space formed in the hook. The piston rod is attached to the piston 14 by a threaded bolt 16. The outer end of the cylinder 15 is closed by a closure member 11 attached to the hook in any suitable manner, with the result that an expansible fluid chamber is formed in the cylinder '15 between the closure member 11 and the piston 14. v

A compression spring 18 is positioned between the inner end wall of the cylinder 15 and the inner side of the piston 14 and acts to urge the piston toward the closure member 11.

Fluid under pressure for operation of thepiston 'I4 is supplied to the cylinder 'I5 `through a fluid passage 'I9 in the closure member v'Ir'l to which fluid is conducted by a pipe 36h connected to an external source, not shown. Fluid may appropriately be conducted to the pipe 36h from the exy ternal source through a vconduit extending through the hook body, as shown in Figs. 1 and 4. Y A fluid passage 80 in the wall of the Cylinder 'l5 communicates at one end with the chamber within the cylinder 15, and at its other end with a iluid passage 8l in the closure member 11. A length of iiuid tubing 82 connects the passage 8i to the passage 1I in the sealing plug 6-8.

An exhaust port 83 extends through the inner end wall of the cylinder 15 and allows air `compressed by inward movement of the piston-lato pass out of the cylinder 15. i

In the operation of this modiiied form of the invention, the latch member lBb is normally in the closed position shown in solid lines in Fig. 5, so that the bail-receiving notch I'Ic is closed. When it is desired to open the bail-receiving notch, fluid under pressure is supplied from the external source to the pipe 36h, from which it f passes through the fluid passage 19 into the cylinder 15. The piston 'i4 is moved inwardly by the force of the fluid against the action of the spring 18 and swings i the vv'locking lever 38 counterclockwise about the pivot 39h to move the end 38e of the locking lever 38 out of the notch 12 in the wall of the latch member, thus permitting the latch member to be swung in a counter-clockwise direction, as will now be described. y

After the piston 14 has moved inwardly past.

the entrance to the fluid passage 80, fluid under pressure will pass from the cylinder I into the passage Bil, through the passage 8l, the tube 82 and the passage 'H into the chamber 66. The force oi. the fluid in the chamber 66 will cause the piston 65 to move inwardly against the action of the spring 'llljthus causing the link 63 to move the latch member IGZ) counter-clockwise to the position shown inA broken lines in Fig. 5, until the lower portion ofthe surface 59 of the latch member engages the shoulder 60 which prevents farther movement of the latch member. i

When the latch member is to vbe returned to it closed position, the supply of uid under pressure to the pipe 36h is discontinued, allowing the springs and 18 to return the link 63 and the locking lever 38",-respectively, -to their normal positions. The weight of-the bail I'ld and the apparatus suspended by it from the hook will cause clockwise movement of the latch member |819 to its closed position. When the latch member is in its closed position, the end 38o of the locking lever 38 will swing into the notch 12 in the latch member and lock the latch member against accidental opening.

It willnow be evident that a device has been provided which willallow the latching member of a hook for rotarydrilling rigs to be locked in a closed position and to be opened in a convenient and easy manner. The operation of the latch may be controlled from aposition remote from the hookyet no dangling uid supply lines need be positioned adjacent the hook which might become entangled during they drilling operation.

It will be apparent that many minor changes could be made in the construction shown `without departing from the scope of thevinvention as set out in the appenf ed claims.

"chim .H l f 1. In a hook assembly for-oil well drilling apl0 paratus'comprising ahook and-a hook body, the hook having a vbail-receiving notch, a latch member adjacent said notch selectively movable with .respect to the hook to positions to open and close said notch, a fluid cylinder, a piston reciprocable within said fluid cylinder, means for conducting iiuid under pressure to said fluid cylinder to cause movement of said piston, means operable to move the latch member to one of its said positions from the other of its said positions, and means connected to the piston` to operate said lastmentioned means `when iiuid under pressure is supplied to said fluid cylinder.

2. The apparatus of claim 1 having means for locking the latch member inV its closed position.

3. The apparatus of claim 1 in which the latch member is pivotally mounted adjacent said notch and said last-mentioned means comprises a link connected to said latch member at a point remote from the pivotal axis of the latch member and movable to move said latch member about its pivotal axis from one of its said positions to the other.

4. The apparatus of claim' 3 in which the means connected to the piston comprises aV piston rod attached at one end to the piston and connected at its other end to said link.v

5. The apparatus of claim 1 in which the latch member is pivotally mounted adjacent said notch and which has a locking lever movable selectively into and out of the'path of pivotal movement of the latch member to lock thelatch member'in its closed position and release the latch member for movement to its open position.

6. The apparatus of claim 5 having fluidoperated means for moving the locking lever away from its locking position and means yieldingly urging the locking lever into its said lock-V ing position.

7. The apparatus of claim 6 in which said fiuid-operatedmeans comprises a second iluid cylinder, a second piston positioned in said second iiuid cylinder, means for conducting iiuid under pressure to said second fluid cylinder, and

i means operatively connecting said second piston to said locking lever, to cause movement of said locking lever out of the path of movement of the latch member when iluid under pressure is admitted to said second cylinder. v

8. The apparatus of claim 1 in which the latch member has an extension portion and said lastmentioned means comprises a bell crank lever pivotally mounted on-saidhook with a nrst one of its arms positioned to bear against said extension portion of the latch member, and said means connectedV to the piston contacts the second arm of said bell crank lever to move said lbell cranklever in a direction to cause its said first arm to move the latch member from one of its said positions tothe other of its said positions when iiuid under pressure is admitted to said iiuid cylinder.`

9. The apparatus of claim' 8 in which said second arm of the bell crank lever has a push rod connected thereto and the push rod is yieldingly urged to a position tending to move said first arm of the bell crank lever away from the extension portion of the latch member.

10. The apparatus of claim 8 in which said means connected to the piston comprises a pivotally-mounted locking lever connected at one end to the piston, its other end engaging the second arm of the bell crank lever, and means for yieldingly urging said second arm of the belly crank lever against said other end of the locking ll lever to move said other end of the locking lever vinto the pathv of movement, ofV the latch member to said one of its said positions.

11. The apparatus of claim 8 in which the latch member has a pair of spaced projections extending therefrom and said rst arm of the bellcrank lever is positioned for movement between and for engagement with said projections, saidfirst arm of the bell crank lever'is yieldingly urged against one of said projections to move the latch member` to onev of its said positions and said iirst arm of the bell crank lever is moved when uid under pressure is supplied to said fluid cylinder against the other of said bearing projectionsA to move lthe latch member to the other of its said positions.

12. In a hook4 assembly foroil well drilling apparatus comprising a, hook anda hook` body, the hook having a bail-receiving notch, a latch member pivotally mounted adjacent said notch selectively movable with respect to the hook to positions to open and close said notch, a piston reciprocable within a chamber formed inv said hook, means sealing one end of said chamber, said piston and. said sealing means dening. the ends of an expansible` fluid chamber, means for conducting uid under pressure to. said expansiblechamber to cause. movement of the piston, means operable to move the latch member. to its open position from its closed position, means connected to the piston to operate said lastmentioned means when iiuid underpressure is supplied to said expansible. chamber, said means connected to the. piston comprising a pivoted locking lever connected tothe piston at one end and havingits other end .normally positioned in the path of movement of aportion of.- said latch member from itsvclosedv position toA itsvopen position, and means yieldingly urging said locking lever to. its normal. position, said locking lever being so arranged. that movement of the; piston inresponse to supply offuid under pressureto said. expansible, chamber.. causes movement of thelocking lever away fromy its normal position out of the path of movement of saidlportion-of the latch member to permit the latch member to moveto its open position when fluid under pressure is supplied.` to said expansible chamber.

13. In a hook assembly for oil. well drilling apparatus comprisingr a, hook and hook body, the hook having a notch for receiving-a bail, a latch member pivotally mounted adjacent saidA notch selectively movable with respectto the hook to positions to open and close said notch, said latch member having' an extension portion` adapted to support a bail and extending inwardly from the pivot point of thelatch member into a space formedv within said hook, thev bail urgingsaid latchmember to its closed position when it is supported on said' extension portion thereof, a piston positioned in a chamber Vformed by the walls bounding said space, a, sealingaplugat one end of said chamber, said piston and said=sealing plug defining the ends of an expansible fluid chamber, means for conducting uid under pressure to said eX-pansible chamber, a bell crank lever pivoted on the hooklwithin said space and having one arm positioned at'one sideof the extension portion ofthe latchl member, means yieldingly urging said onearm of the bell crank lever away from said extension portion of the latch member, a locking leverpivotedintermediate its ends connected-atene .endito the vpiston and bearing adjacent. itsother. end against the otherarmcofy said bell. crank-lever, said other end ofthe locking leverY being urgedby the lastmentioned means 'to a position in the path vof movementV of said extension portion of the latch member to the open position of the latch member, supply of fluid under pressure to said -expansible chamber causing the piston to move the locking lever out of the path of the extension portion of the latch member to the open position of .the latch member and against said other arm of the bell crank lever to move the bell crank lever against said last-mentioned Ameans in a direction to cause said one arm of the bell crank lever to engage theextension portion of the latch member and move the latch member to its open position.

14 'In-o a hook assemblyfor oil well drilling apparatus comprising a hook and a hook body, the hook having a notch for receiving a bail, a latchmember pivotally mounted adjacent said notch and selectively movable with respect tothe hook to positions to open and. close said notch, said latch member having a portion thereof adapted to support a bail and extending` in.- wardly from thepivotpoint. ofv the latch member into a'space formed in the hook, a pistony positioned in a chamber formed by the wallsv of said space, sealingv means. adjacent one end of' said chamber, the piston and the sealing means dening the ends of an expansible iiuid chamber, means for admitting uid under pressureto said expansiblev chamber, means operable to movethe latch member to its open positiony from its closed position, and means connected to the piston to operate said operable means when fluid under pressure is admitted to said expansible chamber.

15. In a hookY assembly for oil well drilling apparatus comprising a hook and a hook body, the hookhaving a notch for receiving abail, a latch member pivotally mounted adjacent said notch and selectively movable with respect tothe hook.y to positions to open andclose said notch, said latch member having; a portion adapted to support a` bail and extending inwardly from the pivotal axisof the latch member, thebail urging said latch member tof its.4 closed position when it is supported onsaid extensionportionthereof, a fluid chamber inl the hook, a piston in said chamber, means for conducting fluidunder-pressurev to said fluid'Y chamber, means connectedv to. the piston operable uponmovement of thepiston in response to admission of fluid under pressure tQsaiduid chamber` toswing the latch member aboutv its pivotalaxis from. itsclosed position to its openlpositioma fluidcylinder, a secondpiston in saidfluid cylinder, means. forv conducting'. fluid under pressure to said fluid cylinder, the bailsupporting portion of the latch memberr having a notch formed therein, a pivoted locking lever having one. of its ends yieldingly urged into said notch to lock the latch member against movement to its. open` position, meansso iconnecting theother end of. said lockingv lever to A`said second piston4v that movement of said. second pistonY in response. to admission of uid under pressure into saiduid-cylinder. causes movement of said one. endof the lockingl lever out-of said. notch, whereby said latch member is normallyllocked in its closed. position but is unlocked Atherefrom when, fluid under pressurer is. supplied to. said fluidcy-lnder, and is movedto its open vposition when uidvunder pressure is suppliedto saidriiuid chamber, j y V l 16. In a hook assembly for oil welldrilling apparatus comprising a hook and a hook-body, the, pk.- havins amich; for. receivinela v.b1-11,11 a

latch member pivotally mounted adjacent said notch and selectively movable with respect to the hook to positions to open and close said notch, said latch member having a portion thereof adapted to support a bail and extending inwardly from the pivotal axis of the latch member, the bail urging said latch member to its closed position when it is supported on said eX- tension portion thereof, 'a first fluid chamber in the hook, a first piston in said first chamber, means for conducting fluid under pressure to said rst chamber to cause movement of said first piston, means connected to said first piston movable by movement of said first piston to move said latch member from its closed position to its open position, a second fluid chamber in the hook, a second piston in said second chamber, means for sealing one end of said second chamber, means for conducting liuld to said one end of said second chamber to cause movement of said second piston, said portion of said latch member having a notch formed thereon, a pivoted locking lever having` one of its ends yieldingly urged into said notch to lock the latch member against movement from its closed position to its open position, said locking lever having its other end so operatively connected to said second piston that supply of fluid under pressure to said second chamber causes movement of said second piston away from said one end of said second chamber to a predetermined position in said second chamber and moves said locking lever out of said notch, a uid conduit communicating at one end with said second chamber at a point between said predetermined position and said one end of said second chamber and at its other end with said means for4 conducting fluid under pressure to said first chamber, whereby supply of uid under pressure to said one end of said second chamber causes movement of said second piston to said predetermined position to move said locking lever out of said notch to unlock the latch member and allow the fluid to enter said fluid conduit and now to said rst fluid chamber to cause movement of said first piston to move the latch member from its closed to its open position.

17. In a hook assembly for oll well drilling apparatus comprising a hook and a hook body, the hook having a notch for receiving a bail, a latch member adjacent said notch selectively movable with respect to the hook to positions to open and close the notch, and means mounted on the hook assembly operatively engaged with said latch member and operable to move said latch member from its closed to its open position.

18. In a hook assembly for oil well drilling apparatus comprising a hook body having a iluid chamber therein, a piston reciprocable within said fluid chamber, a piston rod movable with said piston, a hook having a shank connected to said piston rod and means for supplying fluid under pressure to said iiuid chamber to move said piston, said hook having a notch for receiving a bail, a latch member mounted on said hook selectively movable to positions to open and close said notch, means operable by fluid under pressure to move said latch member from one of its said positions to the other, and means lncluding a conduit extending longitudinally within the piston rod for supplying fluid under pressure to said means operable by fluid under pressure.

19. The apparatus of claim 18 in which said piston rod has a central passageway therein extending longitudinally thereof, and said conduit comprises a fluid-conducting tube mounted at one of its ends on the hook body and extending within said passageway. said tube being so arranged in said passageway that the piston rod is longitudinally and rotatably movable with respect to the tube.

20. The apparatus of claim 18 in which said fluid-supplying means includes a pipe mounted on said hook body, and means mounted on said piston for rotatably connecting one end of the pipe to one end of said conduit.

CLAUDE MCJUNIS ROBERSON.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 1,630,456 Wehr May 31, 1927 1,825,018 Smith Sept. 29, 1931 2,182,214; Sargeson Dec. 5, 1939 2,236,761 Nicholas Apr. 1, 1941 2,370,528 Fontaine Feb. 27, 1945 2,435,119 Baker Jan. 27, 1948 2,527,922 Falkner Oct. 31. 1950 

